Valve structure with o-ring seal



United States Patent lnventors App]. No. Filed Patented Assignee VALVESTRUCTURE WITH O-RING SEAL 1 Claim, 7 Drawing Figs.

11.8. C1 l37/625.48 int. Cl Fl6k 11/07 Field ofSearch l37/625.48,

[56] References Cited UNITED STATES PATENTS 2,887,127 5/1959 Broadbent25l/367X 3,115,701 12/1963 Jones 29/235X Primary Examiner-M. Cary NelsonAssistant Examiner-Michael O. Sturm Attorney-Wolfe, Hubbard, Leydig,Voit & Osann ABSTRACT: A sleeve having axially spaced external groovesand O-rings seated in the grooves form an assembly which is telescopedendwise into a bore to form seals for confining the flow of fluidthrough an intervening port in the bore and a hole in said sleeve. Thesleeve and ring assembly is first inserted endwise into an imperforatetube smaller than the bore wall and larger than the sleeve so that,during the insertion of the tube and sleeve assembly, the O-ring iscovered as it is moved past the edge of the port. After withdrawal ofthe tube from the bore, the O-ring is left unmarked with its originalexternal surface contour expanded against the bore wall.

VALVE STRUCTURE WITH O-RING SEAL 7 BACKGROUND OF THE INVENTION Theinvention relates to the formation of axially spaced rings seals betweenthe internal wall of a bore and a sleeve telescoped into the bore andcarrying O-ringsdisposed in axially spaced external grooves andcompressed against the bore wall to establish communication between aport in the bore wall and a hole through the side of the sleeve.l-Ieretofore, it has been necessary to compress the O-rings as theyenter one end of the bore and are slid along the bore wall past the wallport. Frequently, the surfaces of the ring are cut by the sharp edges ofthe port thus necessitating extensive and costly procedures to test theeffectiveness of the-seal and replace any ring that has been damaged.

SUMMARY OF THE INVENTION The valve structure of the present invention isproduced by compressing the O-rings and effectually covering andseparating the outer surfaces thereof from the bore wall while thesleeve and ring assembly is being inserted endwise into the bore and oneor more of the rings is passing the edge defining the port in the borewall. This is accomplished by first inserting the assembly endwise intoan imperforate tube whose wall is thin enough to telescope loosely inthe clearance space between the sleeve and bore wall. After insertingthe sleeve, ring and tube assembly into the bore to the final positionof the spaced rings relative to the port and the sleeve hole, the tubeis withdrawn from the bore and slid off from the inserted sleeve thusallowing the rings to expand against the bore wall thus leaving theO-ring in the desired position with its outer surface unmarked andpossessing its original integrity.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary diagrammaticsection of a fluid valve embodying the novel features of the presentinvention.

FIG. 2 is a perspective view of a tube used in assembling the valveparts.

FIG. 3 is a fragmentary cross section showing the initial step in thesleeve and tube assembly.

FIGS. 4 and 5 are diagrammatic cross sections showing successive furthersteps in the assembly.

FIG. 6 is a fragmentary section taken along the line 6-6 of FIG. 1.

FIG. 7 is a fragmentary section taken along the line 7-7 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT The improved O-rings sealedvalve structure is shown in the drawings in connection with aconventional plunger type valve for utilizing the back and forthmovements of a land 10 on the end of a stem 11 to control the flow offluid into and out of the interior of a sleeve 12 through holes l3, l4and 15 in the sleeve, clearance spaces 16 around the sleeve and within acylindrical wall 17 of the valve body 9. The holes extend transaxiallythrough the sleeve and register with annular ports 21 somewhat widerthan the holes and constituting the inwardly opening ends of passages18, 19 and 20 in the valve body through which passages pressure fluid isdelivered to the upper clearance space and to the passage 20 through theintermediate port when the land is disposed below the centered positionshown in FIG. 1. Alternately and when the land is above the neutralposition, fluid in the passage 20 is allowed to escape to the passage 19through the hole 14, the lower space 16 and the hole 15.

Opposite ends of the clearance spaces are closed by O-rings seals 22 to25 each comprising a ring of resilient material such 1 as relativelysoft rubber disposed and held in an annular groove 26, in the exteriorof the sleeve and having a circular radial cross section of a diameterwhen free, for example .073 of an inch, somewhat greater than thecombined depth of the grooves 26 and the clearance 16 by .006.008 of aninch, between the interior of the wall 17 and the outside diameter ofthe sleeve.

With the O-rings thus sized, endwise insertion of sleeve and ringassembly into the bore 17 in accordance with conventional practice notonly involves compression of each ring as it enters the bore but alsosliding of each ring, except the last, past the edge 27 of one or moreof the ports 21 while under such compression. Such edges, as ordinarilyformed, are apt to remain relatively sharp and therefore likely to cutthe soft ring material then under compression or roll and pinch the sameas it passes the port edges. Because of this, the outer surfaces of theO-rings frequently become so damaged as to prevent the formation ofadequate seals at the ends of the clearance spaces. This not onlynecessitates the performance of extensive and careful tests to determinewhether such damage has occurred at any one of the several seals butcostly replacement procedures and retesting if such damage is found tohave occurred.

The present invention provides a method of assembly which eliminates thedanger of such damage to the O-rings no matter how many are involved aswell as the necessity of costly testing after the assembly. In attainingthis objective, advantage is taken of characteristics of the structuredescribed above, particularly the substantial radial clearance that maybe employed between the interior of the bore and the exterior of thesleeve and the extent of compressibility of those portions of theO-rings which, when free, project outwardly beyond the sleeve when therings are unconfined as shown in FIG. 3.

Accordingly, the invention contemplates covering the outermost areas ofthe ring surfaces by a thin but nevertheless rigid tube 28 having anuninterrupted internal surface with which the sleeve and ring assemblymay be telescoped slidably without danger of damage but which may beinserted endwise into the bore wall (FIGS. 4 and 5) and later withdrawnwhile leaving the sleeve and ring assembly within the bore. As the end29 of the tube passes each successive ring during such withdrawal, thering expands and becomes compressed against the wall to provide thedesired sealing pressure.

To the foregoing ends, the tube is made of metal about .002 of an inchthick and somewhat longer than the sleeve 12 and formed with a head 30which may be grasped conveniently to effect insertion of the tube andsleeve assembly (FIG. 4) and withdrawal of the tube while the sleeve isheld in its final inserted position against a stop 32 as shown in FIG.5. Insertion of the sleeve and ring assembly into the tube isfacilitated by beveling the outer end of the head 30 as indicated at 33,the outer edge 34 of the bevel being larger in diameter than the maximumdiameter or the O-rings when free and uncompressed. The internal surfaceof the tube which is engaged by each ring during its insertion iscontinuous and uninterrupted thus eliminating any danger of cutting orpinching the rubber of the ring.

In practicing the improved method, the O-rings are first seated in theexternal grooves 26 of the sleeve. Then, with this assembly aligned withthe head end of the tube 28, the sleeve is forced endwise into the tube,the successive O-rings engaging the smooth surface of the bevel 33 asshown in FIG. 3 so as to be compressed and guided into the tube proper.After full entry of the sleeve assembly into the tube as shown in FIG.4, the tube is inserted endwise into the bore 17 until its end 29 comesagainst the stop 32 (FIG. 5), the head 30 then being spaced above theopposite end of the sleeve. In this position of the sleeve, the sleeveholes I3, 14 and 15 will be in proper registry with the annular ports 21in the bore wall. Finally, by maintaining this position of the sleeve aswith the aid of a rod 31 inserted through the head 30 and held againstthe outer end of the sleeve, the head is grasped and the tube is pulledout of the bore leaving the sleeve assembly in the desired positionagainst the stop 32 as shown in FIG. I. This position is maintained by awasher 36 abutting the outer end of the sleeve and secured to the valvebody by a screw 37.

It will be apparent from the foregoing that during insertion of thesleeve and ring assembly into the tube, the surfaces encountered by therings are continuous and uninterrupted and free of edges 27 such asthose of the ports 21 by which the ring material could be cut orotherwise marked in a manner that would result in an imperfect sealsubject to leakage under the high pressures usually encountered inservice use of valve structures of the character described. As a resultof such covering by the tube during insertion of the tube and sleeveassembly into the bore to the final position (FIG. 5), the rings 22 aremoved past the edges 27 of the ports in the bore wall without anycontact therewith. The original integrity of the exposed surface of thering is thus preserved and remains after withdrawal of the protectingtube out of the bore to allow the material of the rings to expand andbecome compressed against the bore wall around areas spaced axially fromthe ports 21. Effective sealing of each clearance space 16 at oppositeends thereof is always assured thus obviating the necessity of testingthe final assembly under simulated service conditions.

The method of assembling the O-rings disclosed herein forms the subjectmatter of our copending divisional application Ser. No. 34,1 15, filedMay 4, 1970.

lclaim:

l. The combination of, a body having a cylindrical boreT a passage insaid body adapted for the flow of fluid through the wall of said boreand terminating at a port at such wall and intermediate the endsthereof, a sleeve inserted through one end of said bore to apredetermined telescoped position therein, said sleeve being smaller indiameter than said bore so as to provide a surrounding clearance space,a hole extending transaxially through one side of the sleeve andproviding for the flow of fluid between said passage and the interior ofthe sleeve, axially spaced annular grooves formed in the outer wall ofsaid sleeve and disposed on opposite sides of said port and said hole,O-rings of resilient material seated in said grooves and forming aunitary assembly therewith, said rings, when said assembly is telescopedto said position, being compressed between said wall and the bottoms ofsaid groove to close the ends of said clearance space, a first one ofsaid rings being moved past and beyond said port during endwiseinsertion of the sleeve and ring assembly into said bore to saidpredetermined position, the outer surface of said first ring in saidposition being unmarked and possessing its original integrity by virtueof being covered and separated from said bore wall and the edge of saidport during the insertion of said assembly into the bore.

